Enclave

Girl15 has always wanted to be a Hunter. They are the ones who are allowed to go outside the enclave, to the ruined world, and bring back food. She isn't good at making things, so she doesn't think she'll be a Builder, and the mere thought of being a Breeder fills her with dread. So at her naming ceremony, when she receives the six scars that make her a Huntress, along the the name Deuce, she is ready to prove herself to the rest of her enclave.

Deuce's hunting partner is Fade, a strange, aloof boy who was raised outside of the enclave. She doesn't really trust Fade at first. After all, he was raised outside the enclave. But after Fade watches her back in a few fights with the mutated Freaks that live outside, an uneasy trust grows between them. Then they find an odd collection of papers in a ramshackle building, and they also find people who have formed their own community against the Freaks. But when Deuce and Fade tell the authorities of the enclave, they are instructed to be quiet under pain of death.

The enclave is wrong.
The perpetual night that holds the enclave in thrall may not be real.